Pygame Move And Jump Example

# Rough example. How to move and jump.
import pygame
import os

from pygame.sprite import Sprite, Group

class State:
    def on_draw(self, surface): pass
    def on_event(self, event): pass
    def on_update(self, delta): pass

class Engine:
    @classmethod
    def setup(cls, caption, width, height, center=False):
        pygame.display.set_caption(caption)
        cls.surface = pygame.display.set_mode((width, height))
        cls.rect = cls.surface.get_rect()
        cls.clock = pygame.time.Clock()
        cls.running = False
        cls.delta = 0
        cls.fps = 30

        if center:
            os.environ['SDL_VIDEO_CENTERED'] = '1'

        cls.state = State()
        cls.extension = {}

    @classmethod
    def mainloop(cls):
        cls.running = True
        while cls.running:
            for event in pygame.event.get():
                cls.state.on_event(event)

            cls.state.on_update(cls.delta)
            cls.state.on_draw(cls.surface)

            for extension in cls.extension.values():
                extension.update(cls)

            pygame.display.flip()
            cls.delta = cls.clock.tick(cls.fps)

class OnKeys:
    def __init__(self):
        self.on_keys = []

    def add(self, method):
        self.on_keys.append(method)

    def update(self, engine):
        keys = pygame.key.get_pressed()
        for method in self.on_keys:
            method.on_keys(keys, engine.delta)

class SimpleSprite(Sprite):
    @classmethod
    def load_image(cls, w, h):
        cls.image = pygame.Surface((w, h))
        cls.image.fill(pygame.Color('dodgerblue'))

    def __init__(self, position, anchor="topleft"):
        Sprite.__init__(self)
        self.image = SimpleSprite.image
        self.rect = self.image.get_rect()
        setattr(self.rect, anchor, position)

class MoveSystem:
    def __init__(self, sprite, speed=0.03):
        self.sprite = sprite
        self.speed = speed
        self.direction = pygame.Vector2(0, 0)
        self.position = pygame.Vector2(sprite.rect.topleft)
        Engine.extension['onkeys'].add(self)
        self.jump = JumpSystem(self, 30)

    def move(self, vector):
        self.position += vector
        self.sprite.rect.topleft = self.position

    def on_keys(self, keys, delta):
        if self.jump.active:
            self.jump.move(delta)
        elif keys[pygame.K_SPACE]:
            self.jump.move(delta)
        else:
            x = 0
            if keys[pygame.K_LEFT]:
                x -= 1

            if keys[pygame.K_RIGHT]:
                x += 1

            self.direction = pygame.Vector2(x, 0)
            if x != 0:
                self.move(self.direction * self.speed * delta)

class JumpSystem:
    def __init__(self, move_system, jump_height):
        self.move_system = move_system
        self.jump_height = jump_height
        self.max_height = 0
        self.height = 0
        self.active = False
        self.action = None

    def move(self, delta):
        if self.action is None:
            self.action = self.jump_up
            self.active = True
            self.move_system.direction.y = -1
            self.height = self.move_system.position.y
            self.max_height = self.height - self.jump_height

        self.action(delta)

    def jump_up(self, delta):
        direction = self.move_system.direction
        speed = self.move_system.speed
        self.move_system.move(direction * speed * delta)
        if self.move_system.position.y <= self.max_height:
            self.move_system.direction.y = 1
            self.action = self.jump_down

    def jump_down(self, delta):
        direction = self.move_system.direction
        speed = self.move_system.speed
        self.move_system.move(direction * speed * delta)
        if self.move_system.position.y >= self.height:
            self.active = False
            self.action = None
            self.move_system.position.y = self.height

class Example(State):
    def __init__(self):
        self.sprites = Group()

        sprite = SimpleSprite((50, 500))
        sprite.add(self.sprites)
        MoveSystem(sprite, 0.08)

    def on_draw(self, surface):
        surface.fill(pygame.Color('black'))
        self.sprites.draw(surface)

    def on_event(self, event):
        if event.type == pygame.QUIT:
            Engine.running = False

def main():
    pygame.init()
    Engine.setup("Example", 800, 600, True)
    Engine.extension['onkeys'] = OnKeys()
    SimpleSprite.load_image(20, 20)
    Engine.state = Example()
    Engine.mainloop()

if __name__ == "__main__":
    main()